A man wades with two dogs through floodwaters in Austin, Texas, on Oct. 31, 2013, after heavy overnight rains. / Deborah Cannon, The Austin American-Statesman/AP

by Michael Winter, USA TODAY

by Michael Winter, USA TODAY

Severe thunderstorms delivered a frightening, and in at least one case tragic, Halloween across the nation's midsection Thursday as torrential rains flooded Central Texas, brought threats of tornadoes in several states and knocked down power lines that led to a 9-year-old Tennessee boy's death.

The heart of the Lone Star State was drenched with up to 14 inches of rain. Flash floods killed a motorist south of Austin when he was swept out his vehicle. More than 100 people were rescued or evacuated from the floodwaters that swamped more than 500 homes in the state capital.

"We saw very significant flooding," City Manager Marc Ott said at a midday news conference about noon after a helicopter tour. "In some cases people cut holes through rooftops to have access to the outside."

He said that although there were reported fatalities, "we have many areas that need to be searched."

The downpour began late Wednesday, and by Thursday morning, Onion Creek reached a record high of 41 feet and continued to rise, inundating the Bluff Springs area, officials said.

Sabrina Loyless told the Associated Press that she was awakened around dawn by the screams of her neighbors, who were trapped atop their car. She tried to wade across the street but ended up clinging to tree branches until being rescued by firefighters.

"When I got about halfway across the road, I realized how bad an idea it was," Loyless said hours later, wrapped in a blanket.

A flood warning for the Colorado River remained in effect for Travis, Bastrop and Fayette counties.

But a rain-free evening was expected for Texas trick-or-treaters as the sun broke through and the wicked weather rolled on.

A 9-year-old boy, whose identity has not been released, died late Thursday night in Nashville, Tenn. after being shocked by a downed power line, police said. They are investigating the incident as an accidental death.

Overall, there were five reports of tornadoes on Thursday: Two each in Louisiana and Illinois, and one in Texas, according to the Storm Prediction Center.

The East Coast was set to begin November with more nasty storms that will bring heavy rains and high winds on Friday. The strongest winds are forecast to roar over New England.